Compressed foam gelatin



Patented May 7, 1935 UNITED STATES PATENT OFFICE COIVIPRESSED FOAM GELATIN Samuel E. Sheppard and James H. Hudson, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New York No Drawing. Application March 23, 1933, Serial No. 662,404

8 Claims. (Cl. 87-7) This invention relates to gelatin and to a procusually about 10%, and its melting point is above ess of preparing it in a highly desirable and con- 200 F. Therefore, it is obvious that if the air venient form. One object of our invention is to for drying is introduced at the dry end of the provide a form of gelatin which is readily soluble, sheet of gelatin foam, that is, flows countercuryet convenient for packing and shipping, which rent to the gelatin, it maybe introduced at a tem- 5 can be handled without disintegration, yet can be perature of around 200 F., whereas if the air is inground to a powder without the expenditure of an troduced at the wet end, and flows concurrently excessive amount of energy, and which is free with the gelatin, its temperature must conform from horny, relatively insoluble edges. Another roughly to or possibly be a little higher than the object of our invention is to provide a process of temperature at which the chilled, wet gelatin 10 making such a form of gelatin. Other objects foam melts. will hereinafter appear. The dried foam or crepe is then compressed.

We have discovered a process of making a form This may be done as a continuous process by passof gelatin which contains compressed air cells, ing the band of dried crepe through rolls, or disand have found that such gelatin has all the decontinuously by stacking or baling sections or 15 sirable properties enumerated above. sheets of the crepe and compressing them in a According to our process, an aqueous solution of hydraulic press. If rolls are used, they may be gelatin is first converted into foam by agitating warmed, if desired, to temperatures not to exceed it with air. The concentration of the gelatin solu- 200 F., but we prefer to operate at temperatures ion m y be anyw fr a out 3% to 15%, or of from 70-100 F. The pressure of the rolls or 20 even higher, depending upon the jelly strength at of the hydraulic press is preferably from 500 lbs. the temperature empleyed- We Prefer to 1158 low to 1000 lbs. per square inch. The dried gelatin concentrations, first, because gelatin is extracted foam is thus compressed to approximately /5 of from animal Waste in the o f a t0 uits original thickness. For example, an air dried tiOn, and y foaming it at this dilution We avoid foam produced in accordance with our invention the necessity of concentrating the solution, and from a 5 solution of gelatin weighed 10232 second, the final product obtained from a dilute grams per cc After compression t weighed gelatin solution is more readily soluble in water 01410 grams per cc" the Same as Ordinary fl ke than the product obtained from a more concengelatin However it was fou d to be much more trated solution. The agitation of the gelatin solureadily soluble in water than the flake gelatin 30 h air may be carned out by means of a The size of the air cells in the dried, compressed colloid mill, such as a Hurrell homogenizer, or by foam ranges from 04 mm. to 3 in diameter, means of an injector, such as a Hauk emulsifier, the average being about 1 mm in diameter 9 air passlng through bames Sucks up the By such compression, the air cells in the gelatin hquld and forces It through the 'f foam are compressed, and form minute cells con- The fcam,stru,ctu re of the gelatm. foam 15 then taining air under pressure. The ease of solution by rutmmg. 1t elther Onto chm cooled of our product is due to the compressed air cells Infamy sultabte manner"or Onto cold Water The which it contains. These expand rapidly when 40 f onto a P g g for the product is placed in warm water, causing a drymg bemg can 16 t y means 0 disintegration of the gelatin, so that it swells and warm air, the temperature of which must not be absorbs water rapidly In water at C, the

high enough to melt the t' time required for our compressed foam gelatin The melting points of the chlued gelatin foams to dissolve is approximately one-fourth of the are approxlmately as follows: time required to dissolve an equal amount of 45 ordinary flake gelatin. Our product is free from g gg ggf fg Melting point of horny edges which result from uneven drying in solution chilled mm the preparation of flake gelatin, and which, being more diflicultly soluble than the rest of the gela- Percent F. tin, prolong the time required for solution. Our 50 g 38:38 compressed foam gelatin can, if desired, be readily 10 100-110 ground to fine powder with little expenditure of I work, whereas the grinding of flake gelatin re- The dried gelatin crepe produced by our process quires a large expenditure of work. )ur comhas a moisture content of from about 7% to 12%, pressed foam gelatin is opaque and white 111 ap- 55 pearance, and can be readily impressed with legends or designs, such as trade marks.

What we claim as our invention and desire to be secured by Letters Patent of the United States is:

1. A permanently set sheet of compressed, substantially dry gelatin foam, having an apparent prising agitating an aqueous gelatin solution with,

air to form a gelatin foam, casting the gelatin foam in sheet form, setting the structure of the gelatin foam sheet by chilling, substantially dehydrating the gelatin foam with a current of air at atmospheric pressure substantially warmer than the chilling temperature, and compressing the gelatin sheet to such an extent that it is permanently set in a compressed, flattened condition.

4. A process of producinggelatin containing a substantial number of compressed air cells, comprising agitating an aqueous gelatin solution of approximately 3% to 15% concentration with air to form a gelatin foam, casting the gelatin foam in sheetform, setting the structure of the gela-.

tin foam sheet by chilling, substantially dehydrating the gelatin foam with a current of air at atmospheric pressure substantially warmer than the chilling temperature, and compressing the gelatin sheet to such an extent that it is permanently set in a compressed, flattened condition.

5. A process of producing gelatin containing a substantial number of compressed air cells, comprising agitating an aqueous gelatin solution of approximately 3% concentration with air to form a gelatin foam, casting the gelatin foam in sheet form, setting the structure of the gelatin foam sheet by chilling, substantially dehydrating the gelatin foam with a current of air at atmospheric pressure substantially warmer than the chilling temperature, and compressing the gelatin sheet to such an extent that it is permanently set in a compressed, flattened condition.

6. In a process according to claim 3, the step of setting the structure of the gelatin foam by floating it on cold water.

7. A process which comprises setting thestructure of a gelatin foam by chilling, substantially dehydrating the set gelatin foam with a current of air warmer than the chilling temperature, and

compressing the gelatin foam to such an extent that it is permanently set in a compressed, flattened condition and contains a substantial number of compressed air cells.

8. A process of producing a sheet of compressed, dry gelatin foam, which comprises agitating an aqueous gelatin solution with air to form a gelatin foam, setting the-structure of the foam by chilling, drying the gelatin foam at atmospheric pressure, and compressing it to an apparent specific gravity of approximately 0.14.

. SAMUEL E. SHEPPARD.

JAMES H. HUDSON. 

